War against the Islamic State

Significance

The war against the Islamic State drew together a broad multinational coalition—operating under CJTF–OIR—in response to IS's rapid territorial expansion following its 2014 invasion of Iraq, its widely condemned executions, and its human rights abuses, as well as concern over further spillover from the Syrian civil war. Member states conducted military operations across Syria and Iraq, with smaller interventions later extended to IS-affiliated groups in Nigeria and Libya. The combined effort significantly degraded IS capabilities by around 2019–2020, reducing the organization from a proto-state controlling large contiguous territory to a contained force operating in a small area. As of 2026, fighting in Syria continued at a reduced level, with IS constrained in both territorial reach and force capability, representing a substantial but incomplete outcome for the coalition.

Forces & casualties

Commanders (167)